The lens is arguably the most important part of any camera. The lens, after all, focuses the light and determines the field of view that is recorded on the film.

The Kraken 612 is designed to use large format lenses originally manufactured for 4X5 and larger field-, monorail-, and press cameras because the 6cm by 12cm format requires more coverage than most medium format lenses can provide. The 12cm width of the frame is just short of the 12.7cm (5in = 12.7cm) recorded by a 4X5 camera.

In that way, the Kraken 612 and similar cameras that use the format straddle the line between medium format and large format. The main difference is the function of the Kraken 612 is firmly in the medium format camp as focusing is achieved using a rotating helical instead of bellows; it uses readily-available 120 roll film instead of sheet film; and each individual image is conceived and imagined through a viewfinder instead of being previewed on ground glass.

How to choose a lens

Almost any large format lens with a flange focal distance (FFD–more on this below) between 60mm and 180mm can be used on the Kraken 612. However, there are some limitations.

Shutter

Early large format cameras did not employ shutters and aperture controls integrated into the lens as early film and other plates had very low sensitivity to light in comparison to today’s film. If you plan on using extremely slow film (ISO lower than 1.0), you could get away with using a lens cap as a shutter.

For the rest of users, a shutter-in-lens arrangement is required.

Shutter Size

With lens-in-shutter designs, the shutter has the hardware that mates to the body of the lens. This consists of a cylindrical protrusion at the back of the shutter and a locking ring. The protrusion extends through the lens board and is locked to the lens board by the locking ring.

The lens board on a Kraken 612 sits on the end of a focusing helical. That focusing helical has an inner diameter of 61mm and the shutter threads have to fit inside that.

There are several standard sizes for the hole in the lensboard through which the shutter will mate, the most common being the Copal shutter size numbers:

#00 26.3mm
#0 34.6mm
#1 41.6mm
#3 65mm

While these are the most common, there are many different size conventions should you choose a lens that does not use a Copal shutter. 

In the printing files for the Kraken 612, you will receive three different lens boards, one each for Copal #00, Copal #0, and Copal #1. Should you need a lens board of another size you have the option of either trimming down one of the provided sizes or requesting a specific size from me at no extra charge. However, most lenses will fit the provided lens boards. 

Back Lens Diameter Issues

Lens-in-shutter designs have three major components: The front lens element group; the shutter in the middle; the back lens element group. In some lenses, the back element group is too large to fit in an M65 helical. The maximum size the back element group can be is 61mm